When sodio-malonic ester is condensed with trimethylene bromide the chief product is ethyl pentane tetracarboxylate, tetramethylene dicarboxylic ester being also formed, and from this the free acid may be obtained on hydrolysis.
NH 2, is prepared by the action of ammonia on trimethylene bromide (E.
It forms an addition product with acrylic ester, which on heating loses nitrogen and leaves trimethylene dicarboxylic ester.
It was long supposed that the simplest ring obtainable contained six atoms of carbon, and the discovery of trimethylene in 1882 by August Freund by the action of sodium on trimethylene bromide, Br(CH 2) 3 Br, came somewhat as a surprise, especially in view of its behaviour with bromine and hydrogen bromide.
CO 2 H,with sodium amalgam, by conversion of trimethylene bromide into the cyanide and hydrolysis of this compound, or from acetoacetic ester, which, in the form of its sodium derivative, condenses with j3-iodopropionic ester to form acetoglutaric ester, CH 3 CO CH(CO 2 C 2 H 5) CH 2.
A similar behaviour has since been noticed in other trimethylene derivatives, but the fact that bromine, which usually acts so much more readily than hydrobromic acid on unsaturated compounds,, should be so inert when hydrobromic acid acts readily is one still.
Chem., 1889 (2), 39, p. 8.) Trimethylene diamine, NH 2.
As to the stability of these compounds, most trimethylene derivatives are comparatively unstable, the ring being broken fairly readily; the tetramethylene derivatives are rather more stable and the pentaand hexa-methylene compounds are very stable, showing little tendency to form open chain compounds under ordinary conditions (see Chemistry: Organic).
Perkin, junr., in 1883, that ethylene and trimethylene bromides are capable of acting in such a way on sodium acetoacetic ester as to form triand tetramethylene rings.
NH 2, is prepared by reducing trimethylene cyanide in ether solution by zinc and hydrochloric acid (A.